Hey guys I was wondering if someone could help me with the 30 min buffer/safety period required for arrivals at aerodromes that require an alternate or holding fuel.

1. Does a TTF need the 30 min buffer period before and after?
2. If a TAF indicates a FM or BCMG which shows deteriorating weather indicating an alternate is required. Will it need a 30 min buffer after the commencement of the 'bad' weather AND 'before'?

Hi krugz93,

I am aware this question was from a few years ago but there could be people doing met who are wondering the same thing.

1. TTF does not require any buffer, probably because we deem a TTF being so accurate. (AIP ENR 1.1 11.7.2.9)

2. Yes, however see AIP ENR 1.1 11.7.2.8, which basically states you need to carry fuel for 30 minutes before and after the deteriorations. However, it then goes on to say that if your holding times extends past the 30 min buffer at the end, you only need to carry fuel to reach the end of the buffer. For example, there is a restricting TEMPO on the TAF between 0200UTC and 0400UTC. Applying buffers, we can say it'll be between 0130UTC and 0430UTC. If our ETA was 0300UTC, we'd need to carry 60 minutes holding (or an alternate). If our ETA was 0359UTC, we'd need 60 minutes. However, if our ETA was 0420UTC, we'd only need to carry holding until 0430UTC (10 minutes) to reach the end of our buffer time, instead of the usual 60 minutes that is associated with the TEMPO.

If I've explained something wrong please feel free to reply!

Jono